There is nothing fundamentally new about this. A quasi particle is a state that scatters or propagate just as it were a particle, but in fact, it is just an interference pattern perturbation of the medium considered. In the article, they just made and electron disturb the media by isolating independently 2 different states that a given electron had, its spin and its angular momentum in relation to an atom. These 2 states disturbed the media and the media carried to the measuring device both of these states, without mixing them.
This kind of disturbance is generally very weak, it will be destroyed way before it can cause a fusion process.
